如何使用api获取颜色 ？？急

'建立新工程，在窗体上放置一个commandbutton,一个picturebox,一个textbox；
private declare function choosecolor lib "comdlg32.dll" alias _

"choosecolora" （pchoosecolor as choosecolor) as long


private type choosecolor

lstructsize as long

hwndowner as long

hinstance as long

rgbresult as long

lpcustcolors as string

flags as long

lcustdata as long

lpfnhook as long

lptemplatename as string

end type


private sub command1_click（)

dim cc as choosecolor


cc.lstructsize = len（cc)

cc.hwndowner = me.hwnd

cc.hinstance = app.hinstance

cc.flags = 0

cc.lpcustcolors = string$（16 * 4, 0)


if choosecolor（cc) >= 1 then

picture1.backcolor = cc.rgbresult

text1.text = "颜色值：" & cc.rgbresult

else

text1.text = "你取消了。"

end if

end sub